It is the broad long-term objective of this research effort to reduce dramatically the emotional, social and economic costs of acquired blindness caused by macular disease processes. Disease processes of interest include age-relate maculopathy, the leading cause of acquired legal blindness in older Americans, and diabetes, the leading cause of acquired blindness in working Americans. Unfortunately, patients, despite knowing they are at risk, are generally unaware of adverse retinal events until vision is compromised. If the patient could self- detect retinal events prior to a vision loss, several key clinical and research needs necessary to achieve the long-term goals would be met. these include providing: 1) fundamental information concerning the early natural history of macular disease prior to a visual acuity loss; 2) a firm foundation on which to base rationales for preventative therapies: 3) a sensitive means of evaluating various therapies designed to alter the natural course of the disease process; and 4) mass screening and home monitoring techniques capable of identifying parafoveal and foveal defects needing further evaluation and/or treatment. The short-term objective of the proposed research is to evaluate the efficacy with which existing optimized entoptic viewing techniques will allow at risk patients to self-detect their own macular defects in a noninvasive, cost efficient manner. This short term objective will be achieved by comparing the accuracy and precision with which type I diabetics can entoptically assess their own foveal and parafoveal defects to defects revealed in the patient's color fundus photography and fluorescein angiogram.